Electrical contact apparatus



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July ,1935. (5. G. CROMARTIE ELECTRICAL CONTACT APPARATUS Filed Dec, 519 INVENTOR gal/4M W ATTORNEY Patented July 9, 1935 UNITED STATESeA'rsu'r oFFicE Application December 5, i930, Serial No. 500,208

tact apparatus by means of which electrical contact can be selectivelyestablished or broken, as desired, between the respective contact mem 5bers of two banks of such members, and

thcinvention' has to do particularly with such an apparatus or devicefor use in conjunction with vacuum tubes in a manner described morefully below. 7

It is necessary or desirable in certain instances to open the vacuumtube circuits in radio sets and other apparatus. For instance, in. thetesting of defective vacuum tubes or circuits, it is frequentlydesirable to open the grid circuit; or the filament circuit, or theplate circuit and to place a measuring instrument in that circuit. Also,in connecting. a phonograph reproducer or pick-up into a radio set thevacuum tube circuits must be opened at one point or another. I- In themodern design of radio sets and like apparatus, the circuit wiring. ispractically entirely enclosed and is very diiiicult of access. Also, thecircuit wiring'is so extensive and complicated that any attempt, by one"not particularly skilled, to open circuits or otherwise tamper with thewiring is likely to result in damage. The present invention providesmeans foropening any of the vacuum tube circuits without necessity ofdisturbing the permanent wiring. The invention effects such provisionbysimple means which can be safely used by an unskilled person and whichcan be operated in much less time than would be required to make achange in the permanent on cuit wiring.

An apparatus embodying the present invention may comp-rise, for example,a plurality of primary contact members insulated from each other andadapted to make contact with a plurality of electric circuits. Forinstance-the apparatus may comprise a plurality of post-type contactsmounted on an insulating base and arranged after the manner of thecontacts provided on a vacuum tube base,.so that the apparatus can beintroduced into a vacuum tube socket to make contact with the severalterminals of the vacuum tube circuit. These primary contact members ofthe apparatus are connected respectively to primary switch terminals,the several switch termina'ls also being insulated from each other. Theapparatus further comprises a plurality of secondary contact. membersmounted on an insulating support, insulated from each other, and

being, for instance, in the form of socket-type contacts adapted toreceive the contacts of a vacuum tube. These secondary contact membersare connected respectively with a plurality of secondary switchterminals as are the primary members described above. The apparatus iscompleted :by the provisionoi manually operated switchkmembers adaptedto open and close cir cuit between the primary and secondary switchterminals. Each switch member serves to establish or break electricalconnection between one set of switch terminals, and the closing of oneswitch therefore establishes connection between one primary contactmember and one secondary contact member. The respective switch membersare actuated independently so that any desired combination ofconnections may be established.

The invention will be described further by reference to the accompanyingdrawing, wherein Figure l is a plan View of an apparatus embodying theinvention; Figure 2 is a side elevational view of the apparatus ofFigure 1; Figures 3 and 4 are transverse sectional views taken on theplanes indicated respectively on Figure 2 as ii- 3 and t-t; Figure 5 isa longitudinal sectional view taken on b t of Figure 1; Figure: 6 is'anelevational View showing the details of a switch member and the switchterminals; and Figure '7 is a perspective view of a preferred form orswitch member. I

The apparatus as here shown comprisesa plurality of post-type primarycontact membersdesignated by the reference numeral i, these contacts I!being so spaced and arranged as to fit a standard vacuum tube socket.Primary contact members i are mounted in a basemember 2 of insulatingmaterial, as shown. A plurality of secondary contact memberscorresponding in number and arrangement to contact members i, aremounted in a base member of insulating material. The'secondary contactmembers are, as'shown, socket-type contacts adapted to receive contactposts of the kind provided on the bases of vacuum tubes. Insulating basemember 2, which carries the primary contact. members i, and insulatingbase member which'carries the secondary contact members't', are mountedface to face with an insulating plate or annular disk interposed betweenthem as shown. Thus, each primary contact member 9 is insulated from allof the others, each secondary contact member 3 is insulated from allofthe others, and all of the primary contact members i areinsulated'from all of the secondary contact' members 3: In the use ofthe device for testing vacuum tubes, vacuum tube circuits, and the like,and in other uses described. belowmthe vacuum tube is removed from itssocket and the device is placed'inthe socket with the primary contactmembers i in engagement with the socket terminals. The vacuum tube maythen be placed in secondary con tact members 3, where'it operatesthesame as though it were placed directly in the vacuum tube socket.

Primary switch terminals 0'- andsecondary switch terminals 'l areprovided in conjunction with the respective primary and secondarycontact members I and't? In theembodiment here shown these switchterminals assume the form of metal sleeves extending through insulatingdisks 2, 4 and 5 spun over at their exterior ends as indicated at 8 tothereby hold them rigidly in position in the insulating disks, whereuponthey also serve the purpose of clamping the several disks together.

Each primary contact member I extends through disk 2, being held inposition in disk 2 by reason of shoulder 9 and the retaining spun overportion It] which engage with the opposite sides of the disk, as shown.A fiat metal connecting strip I I is fitted over the end of each contactmember I, lying adjacent the inner face of the insulating disk 2 asshown, and at its opposite end is fitted over a primary switch terminal6. Thus, each primary contact member I is in permanent electricalconnection with a corresponding primary switch terminal 6 through themedium of the connecting strips Ii. Likewise each secondary contactmember 3 is connected to a corresponding secondary switch terminal l bymeans of connecting strips i2. The metal sleeves which constitute switchterminals 6 and I are preferably spaced about the periphery of theinsulating disks so that each switch terminal lies adjacent itscorresponding contact member, thus minimizing the length of theconnecting strips II and I2.

A plurality of independently actuated switch members I3, shown inFigures 6 and '7, are provided to operate in conjunction with therespective switch terminals 6 and I. Each switch member I3 consists of agenerally U-shaped piece of electrically conducting material the legs ofwhich are of diameter such that they fit snugly within the sleeves whichconstitute the switch terminals 6 and "I. The leg portions of the switchmembers I3 are spaced apart a distance equal to the distance between therespective primary and secondary switch terminals 6 and 'I, so that eachswitch member I3 can be placed, as shown in Figure 6, with one of itsleg portions in a primary switch terminal 6 and the other in thecorresponding secondary switch terminal '1, thereby closing circuitbetween corresponding contact members I and 3. The portion of the switchmember I3 which spans the distance between the switch terminals ispreferably flattened out as indicated at I4 so that it can be grippedconveniently to effect manual removal of the switch member from itsterminals or introduction of the switch thereinto. When switch member I3is in position in switch terminals 6 and l, as shown in Figure 6, onepair of contact members I and 3 are thereby placed in electricalconnection. Switch members I3 may be provided in cooperation with eachpair of switch terminals 6 and I which are provided on the apparatus sothat, by introducing or removing the switch members I3 as desired anyone or any group of the secondary contact members 3 may be placed inelectrical connection with the corresponding primary contact members I.If it is desired to permanently interconnect any secondary contactmember 3 with its corresponding primary contact member I, it will beunderstood that the removable switch member I3 may be substituted by apermanent connection between the switch terminals which may convenientlyassume the form of a connecting strip lying on the face of theinsulating disk and extending between the switch terminals that it isdesired to connect permanently.

In the use of the apparatus here shown, the apparatus is placed in avacuum socket, after the vacuum tube has been removed, with the primarycontact members I in contact with the terminals of the socket. The tubeis then replaced by inserting it into the secondary contact members 3.If all of the removable switch members is are in place in the switchterminals 6 and I, all of the vacuum tube circuits are closed and thetube will operate as though it were seated directly in the vacuum tubesocket. The switch members I3 may be identified by suitable marking; e.g., the switch member shown in Figure 7 is marked G signifying that itcontrols the grid circuit. If it is desired to open the grid circuit ofthe tube, the switch member I3 which is marked G is removed by merelylifting it out of its switch terminals 6 and E. This is an extremelyquick and simple operation which can easily be performed by a novice,which requires but a moments time, and which avoids any tampering withpermanent circuit wiring.

Switch terminals 6 and l are preferably of such size as to receive astandard size cord tip in the same way as they receive the switchmembers I3. Thus, after the circuit is opened by withdrawal of a switchmember I3, a measuring instrument, a phonograph reproducer, or any otherdevice, can be connected into the opened. circuit by merely insertingthe cord tips of such device into the terminal sleeves 6 and I whichhave been vacated by removal of the switch member IS.

The specific embodiment of the invention here shown is adapted for usein connection with vacuum tube circuits. It will be understood that theinvention is not limited to this particular use. It is applicable to theselective connection of a plurality of circuit members of any kind witha plurality of other circuit members. The apparatus may be made up as aone-piece unit, as shown herein, but is not necessarily so made. Ifdesired, it may be made in two or more parts. For example, the primarycontact members I, together with their supporting insulating disk 2,might be made up as a separate unit connected by wires to the remainderof the apparatus which comprises the secondary contact members 3, theswitch terminals 6 and I and switch members I3. Or, for example, boththe primary contact members I and the secondary contact members 3 may beprovided as separate units mounted on their respective insulating bases,while the switch terminals 5 and 7 and switch members I 3 are mounted ona separate insulating support whose only function is that of a switchbank. It will also be understood that the specific form of switchterminals and switch members shown herein may be varied. So, also, ifdesired, the number of secondary contact members may not always be thesame as the number of primary contact members, and certain switchterminals may be connected to a plurality of contact members instead ofto only one member as in the embodiment here described. Themodifications suggested just above are illustrative of various formswhich the apparatus of the invention may assume, and it is understoodthat variations from the specific apparatus shown may be made within thescope of the invention as defined in the claims appended hereto.

I claim:

1. Electrical contact apparatus of the class described which comprises abase of insulating material, a plurality of primary contact memberscarried on said insulating base, a corresponding number of primaryswitch terminals secured to said base, permanently connected flat metalstrips lying adjacent one face of said insulating base and connectingthe respective primary contact members with the corresponding primaryswitch terminals, an insulating member placed adjacent said connectingstrips as insulation therefor, a second insulating base, a plurality ofsecondary contact members carried by said base, a plurality of secondaryswitch terminals affixed to said. base, fiat metal strips lying adjacentone face of said insulating base for connecting said respectivesecondary contact members with the corresponding secondary switchterminals, said second insulating base being placed against saidinsulating member so that an assembly unit having the primary andsecondary contacts exposed at its respective faces is formed, saidswitch terminals extending through the two insulating bases and theintermediate insulating member and serving as clamping means therefor,and independently actuated switch members for selectively controllingthe connections between the said primary and secondary switch terminals.

2. Electrical contact apparatus of the class described which comprises abase of insulating material, a plurality of primary contact memberscarried on said insulating base, a corresponding number of primaryswitch terminals secured to said base, permanently connected flat metalstrips lying adjacent the inner face of said base and connecting therespective primary contact members with the corresponding primary switchterminals, a second insulating base, a plurality of secondary contactmembers carried by said base, a plurality of secondary switch terminalsaffixed to said base, fiat metal strips lying adjacent the inner face ofsaid base for connecting said respective secondary contact members withthe corresponding secondary switch terminals, an insulating memberinterposed between the inner faces of said insulating bases to therebyinsulate from each other the electrically conducting parts carried bythe respective base members, said switch terminals being in the form ofhollow sleeves extending through the three insulating members andserving as clamping means therefor, and switch members consisting ofrods of conducting material bent into a generally U-shapedconfiguration, the rod portions forming the legs of said switch membersbeing of such size and so spaced that they fit within said switchterminals and bridge the distance between adjacent primary and secondaryswitch terminals.

3. Electrical contact apparatus of the class described which comprises abase of insulating material, a plurality of primary contact memberscarried on said insulating base, a corresponding number of primaryswitch terminals secured to said base, permanently connected fiat metalstrips lying adjacent the inner face of said base and connecting therespective primary contact members with the corresponding primary switchterminals, a second insulating base, a plurality of secondary contactmembers carried by said base, a plurality of secondary switch terminalsaffixed to said base, flat metal strips lying adjacent the inner face ofsaid base for connecting said re-- spective secondary contact memberswith the corresponding secondary switch terminals, an insulating memberinterposed between the inner faces of said insulating bases to therebyinsulate from each other the electrically conducting parts carried bythe respective base members, and said switch terminals being in the formof hollow sleeves extending through the three insulating members andserving as clamping means therefor, and switch members forinterconnecting adjacent primary and secondary switch terminals whichconsist of substantially parallel rod portions adapted to fit closelywithin said switch terminals and being connected by a flattened portionshaped to be conveniently gripped by hand and of such length that thespacing of the rod portions of said switch is equal to the spacingbetween adjacent primary and secondary switch terminals.

4. Electrical contact apparatus of the class described which comprises aplurality of primary post-type contacts arranged on an insulating basein such manner as to engage with the contacts in a vacuum tube socket,whereby the apparatus may be inserted into a vacuum tube socket, aplurality of secondary socket-type contacts arranged on anotherinsulating base and extending oppositely from said post-type contacts sothat upon introduction of said primary contacts into a vacuum tubesocket the secondary contacts extend outwardly from the socket and areadapted to receive contacts arranged as on a vacuum tube base, saidgroup of primary contacts and said group of secondary contacts beingsupported out of direct contact with each other, sleeve-type switchterminals in electrical connection with the respective primary andsecondary contacts, said switch terminals being arranged in pairs aboutscribed which comprises a laminated base, a 1

plurality of primary post-type contacts arranged on said base in such amanner as to engage with the contacts in a vacuum tube socket, wherebythe apparatus may be mounted upon a vacuum tube socket, a plurality ofsecondary socket-type contacts carried by the base and extendingoppositely from said post-type contacts so that upon introduction ofsaid primary contacts into a vacuum tube socket the secondary contactsextend outwardly from the socket and are adapted to receive contactsarranged as on a vacuum tube base, insulating means provided betweensaid group of primary contacts and said group of secondary contacts,sleeve type switch terminals in electrical connection with therespective primary and secondary contacts, each of said tere minalsextending completely through the insulating base and anchored onopposite sides thereof to hold the base together, said switch terminalsbeing arranged in pairs about the periphery of the supporting insulatingbase with the adjacent terminals of adjacent pairs being spaced adistance from each other different from the spacing of the respectivepairs, each pair of terminals comprising one primary and one secondaryswitch terminal, and. independently actuated means for effectingelectrical connection between the members of any pair of saidswitchterminals, said means comprising substantially parallelinterconnected rods of conducting material of such size andso spacedthat they fit within said switch terminals of said respective pairs.

GEORGE GRAHAM CROMARTIE.

